if (command === 'MonsterMover') {
//calculate how mutch event have the name monster
for (i = 1; i <= $gameMap._events.length; i++) {
//If The indexof return -1 , is because is not monster, if return 1 is a monster
if ($gameMap._events[i]._characterName.indexOf("monster")) {
//do something with this event ..
console.log(i + ' monster found ');
}
}
}